Q1/2: How do you select which oils to test? Is there a lab I can send samples of oils to test in similar fashion, and/or would you be able to test samples sent to you? Particularly interested in the new SN+ formulations, and of course QSUD. I do not see OEM formulations, particularly the low viscosity ones from Japanese manufacturers – 0W20/0W16 with high moly content, for example.
Thank you for your time and effort, time well spent reading this blog 🙂
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Hi there, thanks for being a long time reader.
Typically, to justify the time and effort it takes, oils are selected for testing if they are likely to be of interest, and used by a large number of my Blog Readers.
But, there are some brands that have tested so poorly in my previous tests, that I won’t waste my very limited time, to test any more of their products in the future.
I also generally test viscosities that are in the widest use, and are of the most interest, such as multi-viscosity 20wts, 30wts, and an occasional multi-viscosity 40wt.
Oils thinner or thicker than that, either should not generally be used in most applications (thicker oils), or are not used widely enough (the newest watery thin oils) to justify testing. Though that could change over time with the newest watery thin oil’s. We’ll have see how things shake out with those.
There is no lab that performs my proprietary Engineering Test on Motor Oil Wear Protection Capability.
API SN+ formulations will be tested on an individual basis as future tests are performed. There are already some on my Wear Protection Ranking List. It is simply not possible to re-test dozens, upon dozens, upon dozens of oils simply because of the relatively minor addition of the SN+ certification.
Readers can send me oils for testing, if I agree to test them, when my schedule permits. I am currently not accepting any oil for testing because I am simply too busy. And I already have several oils on hand, that are waiting in line for testing when I can get to it.
Thank you for your prompt response, and for the good work you continue to do. If you ever have a slot available, do let me know!
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Hi again,
Thanks for the kind words.
Just to let you know. I don’t send out emails from this Blog. But, Blog readers can check in with me any time, here on this Q&A Section.
Hello, 540RAT,
I have suggested your blog to some people that I know. They seamed verry interested. Just a little disapointed that în your oil list They are just a few european made oils. Maybe you will test some more.
I wish a Happy Eastern!
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Hi again Gabriel,
As I’ve said many times before, I test oils that people send to me for testing, when my schedule allows.
The European oil’s I have tested already, were also available in the US where I am located. So, the shipping cost was not that high for people to send me those oils.
But, for people in Europe, it is just too expensive to pay for the shipping cost, to send me oils that are only sold in Europe.
Hi Rat,
I have a question, more out of curiosity than anything. Why do you think the racing oils that you have tested perform so modestly? With the exception of the Gulf Competition and the Motul 300V, no racing oil on your list is worthy of attention.
1. What do racing oils do (or don’t) differently than regular motor oil?
2. Why the racing offering of an oil brand performs much poorly than the regular variant? (example: Mobil 1 Racing vs Mobil 1 FS; Motul 300V vs 8100 series)
Thank you for your time!
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Hi Timi,
I can’t answer for Oil Companies. You would have to ask them. But, talking to their Customer Service is usually a total waste of time. Because their Agents don’t know much either. About all they can do is provide a little info as to what products they offer. Though you can find that out yourself on the Internet.
We could speculate (guess) the reason is because they sell so little Racing Oil compared to Street Oil, that they don’t want to invest as much money in their Racing Oil. But, guessing of course is not always correct.
Once again, thank you for the continued time spent on providing the valuable information contained in your blog. I have turned a lot of my “car guy” friends on to your blog and I think it has opened a lot of eyes into the world of motor oil performance.
I was wondering if you had any future plans to test the new “amazonbasics” line of full synthetic oil. I am thinking that it is likely a major company making it for them, but it would be interesting to see the results. With how big Amazon has taken off, it wouldn’t surprise me if it started being a big seller….regardless of what the results are.
Thanks,
Ryan
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Hi Ryan,
Thanks for sharing my Blog with others.
Yes, there is no doubt that all Amazon does is put their label on motor oil that is made for them. Many smaller motor oil Companies also do the same thing.
I already have their oil on hand, along with a few other oils, waiting for testing when my schedule allows. Hopefully, I can get to that within the next couple of months.
Thanks 540 Rat for the extremely well done oil testing you do. You blew apart many of the myths I held dear. Being an Aerospace engineer I never got too involved in oil testing and theory but also being a car and motorcycle guy I was following the myths I was so used to hearing.
Have you tested any of the Chinese oil company Sinopec products? Thanks, Glen
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Hi Glen,
No, I have not tested any of those products. Everything I have tested, is shown on my Wear Protection Ranking List.
Hello again.
Regarding The possbilities to send oil to you for testing, could you tell me.,please where should be sent and how much?
Maybe I will find a way to send you some european oils like ELF, Ravenol and why not, The russian Lukoil.
Take care,
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Hi again Gabriel,
I am not accepting any oil for testing at this time, because my schedule is too busy. I only post my Shipping Instructions for a couple of days at a time, when I have the time to accept more oil for testing. And I already have several oils on hand waiting for testing, when my schedule does open up.
My friend and I read your blog with great interest. The information you have provided has really changed our minds regarding how we think about oil and its Wear Protection Capability. We have question regarding oil change intervals for antique cars. Annually, we put 500 miles on our cars and sometimes closer to 1000 miles if we do a tour. We are using Mobil 1 currently and in the past we have changed the oil every fall before their winter nap. With the oil today and much higher prices, we were wondering if we could go longer between oil changes. Thank you.
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Hi there,
Changing the oil once a year in cars like yours is the recommended ideal interval. The aging process for motor begins when the bottle is opened and it is poured into an engine that gets driven.
With the formula variations of different oils, how the engines were operated, evaporation, ambient temperature, moisture in the air, etc, it is difficult to declare an absolute maximum time limit on how long motor oil can safely be left in an engine such as yours.
So, if you don’t want to follow the recommended ideal once a year oil change interval, you will have to decide for yourself how long you want to go between oil changes. Because I don’t have any data for going beyond that ideal recommended interval.
Report on my cars:
1. Nissan Almera 1.6 1997 GA16DE non VTC – 260,000km (161,500mi)on odo:
30,000km (approx. 20,000mi) using Mobil 1 ESP 5w30 in 5,000km (3,000mi) oil change intervals – everything fine – no oil consumption – fine operation
2. Nissan Micra 1.6 2010 HR16DE 110hp (same as US avail. engine) – 122,000km (76,000mi) on odo:
22,000km (14,000mi) using Mobil 1 ESP 5w30 same oil change intervals – everything fine – no oil consumption – fine operation
3. Nissan Qashqai J11 2016 (Rogue Sport in U.S.) 1.5 turbo diesel engine tuned at 148hp (110hp factory output) – 27,000km (16,800mi) on odo:
25,000km (15,500mi) using Pentosin Pento Super Performance III 5w30 same oil change intervals – everything fine – no oil consumption – fine operation (in terms of diesel knocks at idle)
4. Audi 80 coupe 2.2T 230hp 1990 – 187,500km (116,500mi) on odo:
15,000km using Valvoline Max Life 10w40 (Red-Semi Synthetic) 5,000km (3,000mi). With this oil, oil consumption decreased to 0.5qt per oil change interval from 3qts per oil change interval using fully synth 5w40 MAG 1 European formula. 0.5qt is practically no oil consumption cause there’s no need to add during these 3,000 miles (indicator max at oil change to mid at next one).
Reading carefully your blog is a mind opening procedure, using only knowledge from physics and simple engineering to understand how an oil behaves – works. And then, there’s nothing left, but to see these facts working for you on your cars.
Me, personally,
THANK YOU!
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Hi again Emmanouil,
Thanks for sharing the information about how things are working out with your cars.
Hi, 540 RAČš.
First impressions with Amsoil signature 5w30:a slight higher accelerations, maybe due to better flow în The cvvt System. Also improved fuel consumtion on highway:from 7 liter /100 km with two persons, to 6.5 liter with 4, at a speed of about 140 km/hour.
I think I made a good choice.
Thanks for the advice.
Nice weekend!!!
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Hi Gabriel,
Thanks for the feedback. I’m glad to hear that the Amsoil is working out well for you.
Hey there Rat! So I just recently came across this and figured you may be able to help. So on mustangs, the 2013-2014 Boss 302 Coyote motor calls for 5w50 oil. The Gen 2 Coyote (2015-2017 GT) is the exact same motor internally and Ford says it calls for 5w20. What reasoning can you come up with that makes this makes sense? Same motor and Ford saying requires different oils? I have a gen 3 which has been gaining attention due to piston slap and having longblocks replaced. Many people are switching to 5w50 and I can’t get a straight answer to why people are doing this. Do you have any input? Thank you very much for your research and contributions. They mean a lot to us inquisitive type that don’t know as much as you lol.
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Hi Tyler,
Ford and BMW both call for super thick oil in their Higher HP engines. It does NOT make sense to you, because they are dead wrong, meaning it does NOT make any sense at all. This is a huge mistake made by Factories that simply do NOT understand motor oil. Here’s why:
When an oil layer is so thin that it is only an oil “film”, it is the oil’s “film strength” that provides its wear protection capability. And oil film strength is determined by the oil’s additive package, NOT its viscosity.
When an oil layer is thick enough to be actual “liquid” oil, all oils are equal, because all “liquids” are incompressible!!! For that fundamental reason, all incompressible “liquid” oils provide the same wear protection capability. Once again, viscosity has NOTHING to do with the oil’s wear protection capability.
Motor oil viscosity does however, have an effect on oil pressure. But, if an engine is designed properly, thinner reasonable oils can provide excellent oil pressure. So, there is NO beneficial reason to run super thick oils.
So, I am extremely disappointed with both Auto Makers. I would expect much better from them, because they should know better. And BMW had a huge number of rod bearing failures in their High Performance “M” engines, largely because of that.
Ford calls for 5W20 in their normal GT engines, only for slightly improved MPG, and nothing else. That thin oil was forced on Ford Engineers who did NOT want it, just to help increase their C.A.F.E. Numbers. I know this for a fact, because I have spoken with Ford Engineers who told me just that.
“ALL” their Coyote engine variations would be best served with a High Performing 5W30 Motor Oil from my Wear Protection Ranking List, if they are run aggressively at all.
5W20 is thinner than ideal, and anything thicker than 5W30 is thicker than ideal. See my Tech Article on Motor Oil Viscosity Selection, for all the details.
I’m a Degree’d Mechanical Engineer, U.S Patent Holder, Engine Builder, and life-long Mechanic. In fact, I was a Professional Mechanic while going to College. I have wrenched on Cars, Trucks and Motorcycles since I was a teenager.
And I put my money where my mouth is. I have a modified 600 HP Terminator Mustang, 2003 model, which is the first ever Factory Supercharged Mustang. So, taking my own advice, I run 5W30 Quaker State Ultimate Durability full synthetic in it. And the engine is perfect.
I also have 5W30 in my 800 HP, 540 cubic inch, Big Block Chevy Rat Motor. That engine is also perfect.
Using super thick oil is NOT a cure for piston slap, which is caused by excessive piston to cylinder clearance. The cure is to correct the piston to cylinder clearance. And the easiest way to do that, is to replace the engine with a properly built engine. People who switch to 5W50 have no idea what they are doing. Do NOT follow their WRONG idea.
Hi 540,
I have a technical question. Im an engineer, too and i question myself, how your exact bench looks like.
you described, what you basicalle did.
I will try to build….
Greetings, Lukas !
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Hi Lukas,
My Engineering Test Procedure and Test Equipment are Proprietary Intellectual Property. So, the specific details cannot be shared. But, as shown in numerous examples throughout my Blog, including flat tappet cams, the test results exactly match real world experience.
In other parts of your original message not shown above, you are confusing motor oils with increased slipperiness due to them having extra friction reducers, with motor oil wear protection capability. But, slipperiness and wear protection capability are absolutely NOT the same thing.
An extra slippery motor may not provide extra wear protection. And an oil that provides excellent wear protection, may not be extra slippery.
Slipperiness comes from friction reducers. But, wear protection capability comes from the extreme pressure anti-wear components in an oil’s additive package.
I was curious as to your opinion regarding sulfated ash content. I’m currently using Amsoil SS 0w-20 in a 2019 JGC with the 5.7 Hemi, as well as a 2019 JGC with the 3.6 pentastar engine.
Amsoil technical support stated that this oil is at 1% sulphate ash. Your opinion is greatly appreciated.
When your schedule is available I have some oils i’d like to send in for testing.
Thanks,
L.V Thompson
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Hi there,
I have never heard of JGC. It would be helpful if my readers would clarify unfamiliar references.
I would not be concerned about 1% sulfated ash. Sulfated ash comes from the burning of additive components that are used to create the total base number (TBN) acid neutralizer.
That motor oil has an extra high TBN value of 12.5, because it is intended for extended oil change intervals, where most oils typically have a TBN value of around 8 to 9 or so. Since sulfated ash and TBN are of course linked, a higher TBN number will result in higher sulfated ash numbers.
Keep in mind, that oil meets the requirements of API SN Plus and GM dexos1 Gen2, according to Amsoil. Their motor oils are among the best on the market. So, I would have no concern about using that oil.
But, for the record, I am 100% against extended oil change intervals. See my Tech Article on Recommended Oil Change Intervals, for all details.
I already have several motor oils in line waiting for testing. So, it could be a long time before I can accept any additional oils for testing.
I appreciate your input. I should have just said Jeep Grand Cherokee instead of JGC. I agree with you on extended drains, as I change my oil out at 3,000 miles. The tech department from Amsoil responded to me via e-mail listing the Amsoil SS 0w-20 and 5w-20 at 1.22% Sulfated ash content.
Hi 540Rat- I was curious, I recently read about valve spring oilers, and the gist of it was to reduce the temperature of the valve springs. Apparently, in high rpm applications the temperature of the valve springs can get quite high- the article I read claimed the temperature could get to something like 700 degrees ! I can understand how the springs might actually get that hot, but because what read was more or less a sales pitch for their valve spring oilers, was wondering if you knew of any actual experimental data to back it up. Thanks!
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Hi Kevin,
I don’t have any valve spring temperature test data in front of me. And generating our own valve spring temperature data would not be easy to do.
But, I agree, that sounds more like a sales pitch, than something that most people would ever need, because of the valve spring temps they would actually experience.
What they don’t tell you, is that even stock valve springs are typically oiled as part of normal proper engine design.
It would be hard to believe that even NASCAR valve springs would ever see 700*F. They would come to mind as really high rpm endurance engines. They run at around 9,000 rpm, at 190 mph or so, for as much as 500 miles. If ever an engine’s valve springs get worked REALLY hard, it would be theirs. No doubt open wheel race cars like Indy cars would operate in much the same environment.
But, those engines are so highly refined, that I would expect them to already have valve spring oilers, to keep their valve spring temps under control.
For other engines, including other types of race engines, as well as our own engines, I would like to see proof that valve spring temperatures get so high that we need that Company’s valve spring oilers.
I have never had aftermarket valve spring oilers, even in my High Performance engines, nor do I even know anyone who has.
But, with all that said, having valve spring oilers would not hurt anything. So, I have no problem with anyone using them.
Hello 540,
Thank you for answering my question !
That is unfortunate, but understandable.
The section with the slipperness makes absolute sense to me. I can clearly imagine the differences. I think i will give that mobil1 fs 0w40 a try and have a look at if it works.
Before i drove with a cheap oil which is claimed to be just the better one with another label on it. But to be honest i lost my trust in assertions like these. Why should they relabel a 60€-Oil and sell it for 17€ ?
I had put in extra zddp, which i calculated to raise it up to 1400ppm. But like you have shown, this also might have negative consequences. Under circumstances i could have killed the camshaft, even if it was great looking while disassembling (cause of another problem with the engine).
This is now my first experience. Now i want to collect experience in using scientific tested oil and have a look if things look better or even worse with it.
Hello, 540RAT.
I have ordered also Amsoil MT oil, due to good behavior of Amsoil Signature. Am I made a good choice?
Have a nice day!
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Hi again Gabriel,
Amsoil’s products are among the best on the market. So, you should be fine with that.
Hi Rat – I have used oil analysis results from the Lexus I have been running the Renewable Lubricants oil in. The iron numbers are unbelievably low for a 5k mile oil change interval. I’ve got three successive results with the vegetable based oil, they’re all pretty spectacular. If you would like to see what Blackstone found, send me an email at lobuxracer…and I will send you my latest results. I am 100% sold on buying their oil in 5 gallon buckets (I have two cars with almost 10 quarts on an oil change) based on what I am seeing from Blackstone and your confirmation the load capacity is near the top of the chart.
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Hi again,
That is excellent feedback that I thought my Blog readers might like to see. So, I posted it here, without your email address.
I only communicate with my Blog readers here on this Q&A Section. So, no emails are involved. But, feel free to share your Lab Test results here if like.
How do I search your blog? I have tried and everything comes up blank. I even tried simply Amsoil since I know that is in there, but still nothing.
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Hi there,
I explain how to search my Blog right at the very beginning. Check it out and you will be good to go.
I’m participating the less possible in your Q & A blog, but … here is my experience about Tech Article 42 and MAF screen removal issues.
I’ve experienced such a “mess” on my Rogue Sport (EU Qashqai) 1.5dCi (turbo diesel) engine, when I deleted MAF honeycomb, in order to achieve max torque and hp values during ECU reflash at WOT. A final achievement of 152hp instead of 110 at 4100rpm and 244lbft from 191 at 1900rpm are welcome.
But despite its supercharged nature, driveability had some issues when throttle was partly (below 0.5) opened in city driving style. I had my car configured like this for more than a year, with 4 in. of pipe deleted along with the filterbox in favor of a K&N cone filter. These 4 inches were housing MAF screen too.
Finally, a month ago, I replaced the whole system in order to have my K&N under cleaning procedure for a few days, with the OEM filterbox and the whole OEM piping, but with a K&N panel specific 1.5dci filter.
First few miles, and I thought that better throttle response was a placebo effect. 500 miles and I really noticed that this response was not only in my mind. What the hell? I asked a Nissan authorised service store engineer and said that MAF screen is for a purpose.
It doesn’t cost more than 10 euros to Nissan factory and plays a significant role in idle to part throttle modes.
Next step was a visit on dyno to see if 152 hp was still there. No, there were not all of them, but consider this: 150.3 hp is not a cry-for loss. On the other hand, better throttle response and faster turbo spool-up at POT (part open throttle) improved everyday driveability.
Apart from this, 241lbf of max torque are available @ 1750rpm instead of 1900+ rpm.
I wrote all these, because Tech Art. No.42 describes a fact that applies to turbo diesel engines too, as far as I’m concerned.
E.C. Greece
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Hi again Emmanouil,
Thanks for sharing that your experience was exactly the same as my new Tech Article 42 describes regarding MAF sensor screen removal. And yes, this applies to all engines.
I’m happy to share my results, just not sure how to do that with this interface. I get a PDF from Blackstone. Converting it to anything useful is really ugly. My iron numbers have been 13, 7, 6, 5, and now 4 (ppm) for the last run with a typical interval of 5k miles +/- a little. The iron numbers mean the most to me as iron in suspension is the most abrasive element they check in their testing. My other Lexus doesn’t produce numbers anywhere close to this. The 6, 5, and 4 numbers were all from Renewable Lubricants products, previously I ran Mobil 1 5w-30. I tried Renewable PCMO and HDMO and got slightly different, but still very similar results. I have decided to stick with their PCMO simply because the HDMO has a lower thermal breakdown number. Both clearly provide excellent service and both are unusually stable as evidenced by their ability to maintain load capacity at elevated temperatures. I doubt anyone would be unhappy with either. I recently discovered they have submitted a product for API certification, but when I looked at the numbers they provided, it didn’t look as capable as PCMO or HDMO.
In the end, I am happy to save the underground petroleum for purposes only it can fill while I put a biodegradable product in my engine that rivals the best of the best for performance.
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Hi there,
Are you going to test the Amazon Basics 100% synthetic in either 0-20 or 0-30? Im wanting to see how it compares to Walmart 0-20 100% synthetic. They are both inexpensive to buy and I would get whichever one tests better. They are also very popular and used by 100s of thousands of people. Thanks for your blog. Your ranking system goes along with what works on the street! Keep up the good work.
Doug Burnham
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Hi Doug,
I just tested 5W30 amazonbasics full synthetic, because 5W30 is the most commonly used viscosity overall, and is of the most interest to the most people.
I will be posting that test data along with test data from several other oils, within the next couple of days. So, you can then directly compare 5W30 amazonbasics synthetic with 5W30 Walmart synthetic.
I have a high mileage 1966 ford and I like the idea of using the high mileage oil to minimize leaks. Can you confirm it’s more beneficial to use conventional oil instead of synthetic to reduce oil consumption? I am currently using the valvoline full syn high mileage silver bottle
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Hi Mark,
Yes, in older engines that use oil, it is well known that they will use the least oil if they are using High Mileage conventional oils vs High Mileage synthetic oils.
For a 1966 engine, I suggest you consider using 10W40 Pennzoil High Mileage Vehicle Conventional oil.
540 Rat there is another web site that they say use your information but they don’t have Amsoil listed at number 2 or 3 . Is Amsoil holding 2 and 3 right on. Or has something changed.
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Hi there,
I have “NO” connection to any web site that uses my Engineering Test Data. So, I have no idea what they do with my Test Data.
I suspect what you might be seeing on that web site, is that they did not include “ALL” the oils on my Wear Protection Ranking List, which throws off the ranking numbers they show. If they are doing something more sinister, then they are fraudulently manipulating my information.
You should only come to my Blog to see the FACTS from my Engineering Tests on motor oil. You should not be looking at some second party web site using my information. Because not only can they be confusing, but they could also be providing completely wrong information, that didn’t even come from me.
If you look at my own Wear Protection Ranking List, you will see that Amsoil is ranked 2nd and 3rd. The oil ranked 1st on my list, is an oil that had an aftermarket additive put in it, which I tested for informational purposes only, because of a request I had at that time, to test that additive.
But, I do NOT recommend using any aftermarket additives at all. Because they can make a motor oil WORSE OVERALL, due to upsetting the carefully balanced factory additive package, no matter what it may or may not do for the oil’s wear protection capability. So, I no longer accept any Aftermarket Additives for testing, since it can give my Blog readers the wrong idea about using them.
An excellent performing motor oil will NOT need any help. If you have an oil that needs help, you are using the wrong oil. Anyone can easily find an excellent performing motor oil on my Wear Protection Ranking List, which they cannot find anywhere else.
540RAT: Very informative blog and I like the attention paid to shear strength of the oil. In the end that is what keeps parts apart when running at op temp. Also the emphasis on oil flow as key … this has informed me greatly on my choice of oil for my new car.
1) I don’t, however, agree with your opinion on computed oil change intervals. I read (for example) the published paper[1] by Honda on how they arrived at their algorithm for the oil change and it is scientifically, statistically, engineering based through and through – that should meet your standards …. (The owner’s manual still says 1 year max, however, in the case of my car but my oil won’t last that long with my mileage). Yes, I did read your points about the depletion of the additive pack and accumulation of chemical contaminants. That said, I’ve never been disappointed by Honda’s engineers over the last 30+ years and my girlfriend’s first Honda Fit did a lot of road (sales) based on the minder with no issues until she sold it with over 300km (and bought another Fit, of course).
2) Have you spoken with API or oil makers about adding shear strength at operating temperature to oil labels?
3) You say you have no skin in this game. If so, and for the benefit of gear heads everywhere, why not publish the method and apparatus?
Cheers,
The Bull.
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Hi Bull,
1) I do NOT express opinions, nor theories, nor do I speculate in this Blog. I share FACTUAL Engineering Test Data that is determined by the Science of the Physics and Chemistry involved in the testing.
And I provide various recommendations for the BEST way to care for engines, based on reasons I state, which also takes into account decades of hands-on engine experience, and that is all backed-up with being a long time Mechanical Engineer.
My recommendations come from everything just mentioned above, so they are not up for agreement or disagreement. This Blog is not an open debate. If you are looking for that, you need to move on to a Forum, where you can argue endlessly to your heart’s content.
Manufacturers suddenly changed to ridiculously long oil change intervals, with no motor oil changes and no engine changes, only to reduce their “cost of ownership” numbers, regardless of what their propaganda may say.
Using ridiculously long oil change intervals does NOT benefit an engine in any way. It only reduces the Owner’s financial expenditure related to changing the oil. That is most certainly NOT the BEST way to care for an engine.
Sharing information about what is FACTUALLY the BEST way to care for an engine, is what this Blog is all about. FACTS MATTER!!!
Keep in mind that the Honda Fit has a VERY LOW performance engine that does not load its oil heavily like a Higher Performance engine does. So, it is not a good example to use, to make the case for extended oil change intervals.
I have experienced complete used oil failure/seizure during testing of used oil that had as little as little as 5,000 miles on it. That is real world test data, not some theoretical algorithm. So, for that reason and all the reasons I discuss in my Recommended Oil Change interval Tech Article, I stand by my recommendations for oil change intervals that are the BEST way to protect an engine.
My Blog readers are of course free to follow my recommendations for their own benefit, or they can ignore my recommendations and do their own thing. It makes no difference to me either way.
2) No, because half the oils on the market would look so bad, that no one would ever buy them. So, the Motor Oil Industry would never agree to do that. Plus, they would just say that an API SN certification already covers that. But, I have determined that an API SN certification is totally worthless with regard to wear protection capability.
3) My Engineering Testing Methodology and Test Equipment are Proprietary Intellectual Property, and cannot be shared.
Hello, again 540RAT,
Just a feedback after 2000km made with Amsoil 5w30 Signature, on Kia ceed 1.4 109 hp:I bearely recognize my engine. Much smooter, lowe fuel consumtion, and the chain noise at idle is reduce drasticaly. Thanks again for your recomandation.
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Hi again Gabriel,
Thanks for your feedback.
But, I do want to be sure everyone is clear about something. I try to not recommend any certain motor oil to people. I have no stake in what motor oil people use.
I provide factual Engineering Test Data, and let people decide for themselves which oil they want to use based on that data.
As I recall, I did not recommend that oil to you. I merely said it would be a good choice, when you asked about it.
Hello, 540RAT,
Sorry for the missunderstanding. Of curse you did not especialy recommended. It was enough for me to look on wear ranking.
Nice weekend!
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No problem.
Did I miss it or was Amsoil 5W20 Signature not tested? I see the results for Amsoil 5W30 Signature.
Is there that much difference in oil weight from 5W20 vs 5W30? Maybe 5W20 better for Midwest winters and 5W30 for summers – correct?.
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Hi Robert,
My Wear Protection Ranking List has 0W20 and 5W30 Amsoil Signature Series oils right at the top. I did not bother to test 5W20 Amsoil SS oil since I had already tested the other two.
5W20 and 5W30 are both rated as 5wt oils when cold, which applies to both cold engine start-up, and during engine warm-up.
But, 5W20 is rated as a 20wt oil at hot operating temperature, while 5W30 is rated as a 30wt oil at hot operating temperature.
So, their viscosities are comparable when cold, but their viscosities are different when hot.
In general, you can just follow your Owner’s Manual’s viscosity recommendation, and use the same oil year around.
But, also be aware that 5W20 oil came about only to slightly help improve Auto Makers’ C.A.F.E. (Corporate Average Fuel Economy) numbers. It did NOT come about to help the engines in any way.
Virtually any engine that calls for 5W20, can also safely use 5W30. In fact, many engines that call for 5W20 are happier, and make less mechanical noise with 5W30.
5W30 is really the best all around viscosity for most engines. I now use 5W30 in my own stock engines that called for 5W20. And I also use 5W30 in my own modified High HP engines.
So, you can decide for yourself what you want to run.
It’s a 2019 KIA Optima and the owner’s manual states both 5W20 and 5W30 – GDI engine. Reading your blog, I thought thinner oil was better?
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Hi again Robert,
Let me clear that up for you and any other Blog readers who may have had the same question.
Part of the confusion probably comes from the fact that my Blog is so incredibly large. So, many important points might easily be missed.
But, In various places in my Blog, I have tried to make it clear that when I’ve pointed out how thinner oils are better, that was primarily aimed at American Hotrod and Race car V-8 guys, who “mistakenly” think that thicker oils, such as 20W50, are needed in High HP engines. But, that is simply not true, and is the “wrong” way to go.
However, modern late model vehicles already call for thin oils. So, they are already doing the right thing.
And like most things in life, there is an optimum motor oil viscosity for most engines. And then there is thinner than optimum, as well as thicker than optimum.
5W30 is the optimum motor oil viscosity overall, for most water-cooled engines, including High HP engines. Any viscosity thinner than 5W30, is thinner than optimum. And any viscosity thicker than 5W30 is thicker than optimum.
So, I personally use 5W30 in all my own engines, from mild to wild. And I recommend that my Blog readers do the same.
In previous Q&A posts, I read that you stated oil burning engines will consume less oil when using conventional oils vs synthetic oils.
My question relates to the oil selection for a Subaru 3.6L boxer engine. Subaru boxer engines are prone to consuming oil, and the Subaru 3.6L OEM factory fill is 5W30 mineral oil. Does it make sense to use conventional oil in this engine given its tendency to consume oil? I would like to select the best type of oil that minimizes the potential for oil consumption.
Again, I appreciate input, and I further appreciate the work you do on this blog.
Regards,
RG
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Hi RG,
Yes, it is well known that engines that consume oil, will consume the least oil when using conventional motor oil.
I appreciate your prompt response…thanks. I have been reviewing 5W30 conventional motor oil wear ratings on your blog. I noticed that the wear rating for Castrol GTX 5W30 SN was pretty good. However, since Castrol updated the formulation to Ultraclean to SN+, the wear rating decreased significantly. I am curious if this is going to be a theme with other conventional motors migrating to SN+.
Any suggestions on a 5W30 conventional oil would be appreciated.
Best,
RG
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Hi again RG,
It is too early to say if SN+ conventional oils in general have reduced capability. The Castrol GTX 5W30 “Ultraclean” SN I tested was NOT SN+, it was just SN.
Something that has become clear in my testing, is Castrol has sadly significantly reduced the capability of their motor oils across the board. Apparently this was done deliberately to maximize profits. So, I completely stopped using their products, and do not recommend them to my Blog readers.
So, I suggest that you consider other conventional oil brands, including High Mileage oils, which can be safely run in engines that are not old. That will give you a wider range of oils to consider.
Would you treat a boat engine any different when it comes to oil selection? I have a 20′ mercuiser V-6 and they always recommend 25-40 oil but after reading your blog I wonder if that oil has that great of protection during start-up. Water-skiing and running at wide open throttle a lot would stress an engine so I want to ensure the best oil is in this engine. 25W oil seems like it would not flow ideally during startup on the lake when its 60 F ambient although I always idle and warm up after starting. Reading through the blog and Q/A i haven’t seen any speak of boat engines at all so im hoping you could let me know your thoughts. Your blog is a pleasure to read-very informative!
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Hi Mark,
If you were running an actual automotive engine in your boat, then all the same recommendations on this Blog would apply.
But, I have no test data on engines designed specifically for boats, such as your Mercriuser V-6. I’m also not specifically familiar with how capable their oiling systems are, relative to their particular bearing clearances. So, to stay on the safe side, I will not suggest changing the hot 40wt viscosity rating.
However, I will say that a cold 25wt viscosity rating is insanely too thick. So, I definitely suggest you switch to a far superior multi-viscosity rating, such as 0W40, 5W40 or 10W40.
A few oils you could consider, are:
0W40 Mobil 1 “FS” European Car Formula, which is currently ranked 6th on my Wear Protection Ranking List.
Or
5W40 Mag 1, FMX, European Formula, which is ranked 29th.
I am currently running QSUD5w20 in my 5.0l jaguar. I want to switch to QSUD 5w30. I see from your results i would’nt be giving up much in wear protection. I am more concerned with mechanical noise(reducing it) and potential engine problems, as jaguar dealers are adamant on 5w20, but i can find no supporting info as to why. Your research suggests 5w30 would be ok. Am i missing something that may be unigue to this engine?.
On another note. I have a 4.0l jeep grand cherokee that i switched over, at 160,000km to highly rated high mileage oil from your list and am happy to say that at 310000km my engine idles as smooth as glass and is quiet. Ive heard other jeeps with less mileage rattling like bolts in a metal can.
Keep up the good work
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Hi there,
5W30 is the optimum viscosity for most gasoline powered, water cooled automotive engines. Virtually any engine that calls for 5W20 can safely use 5W30. Engines that call for 5W20 are typically happier and make less mechanical noise with 5W30. I’ve switched my own late model engines that call for 5W20, over to 5W30. And I would do the same thing with your 5.0 Jag.
Jag Dealers are adamant about using 5W20 only because they don’t know any better. They are just blindly following what is called for.
There is no technical benefit for an engine to use 5W20. In fact Engineers did not want 5W20 in the first place. It was forced upon them by Corporate Management to slightly help Corporate C.A.F.E. fuel mileage numbers. The whole thing was Political, not Technical.
Hi 540 Rat, I have a variation of the question that you just answered for blackjag2. I have a 2016 jeep grand cherokee that calls from 0w-20 (versus 5w-20) and I’ve been using the Amsoil Signature Series 0w-20 as it’s so highly rated by you. Would I also be ok going to 5w-30 in that engine? Thanks! Dan
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Hi,
First of all, i thank you for all informations and experiences you’ve shared with us.
Like most of your readers, i would like to know which oil should i use on my Civic FK7 which has 1.5T DI gasoline engine on it. At that moment, my car is around 5k kilometers and i believe i will have to change the engine oil around 2k kms later. Where i live is quite hot, therefore i would like to know if using an engine oil of 5w30 fits or not?
Thanks in advance for your interest.
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Hi there,
“There is no technical benefit for an engine to use 5W20.”
Is this a departure from your support (cooler oil) for using 5w-20 in engines designed for it.
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Hi there,
I would not say that I was ever a fan of 5W20. It was more that I just grudgingly accepted it in newer engines.
It would be more accurate to say that most of today’s engines can run 5W20, than to say that they were actually designed for 5W20.
5W20 was forced on Factory Engineers in order to slightly improve Corporate average fuel economy numbers. It was not used to somehow be a technical benefit for engines.
If people feel they need to run 5W20 because that is what the Owner’s Manual says, that is fine. It won’t harm an engine that is just a normal daily driver.
But, for engines that are raced, generally driven aggressively, or used in any extreme condition, 5W30 is a much better choice overall. 5W30 is plenty thin enough to provide excellent lubrication and cooling.
In addition to that, if people were to listen closely to their engine at hot idle, they would find that most of them make some mechanical noise when using 5W20. But, when using 5W30, those engine noises are typically eliminated.
Bottom Line: Like most things in life, there is an optimum for almost everything. And when it comes to motor oil, 5W30 is the optimum viscosity for most water-cooled gasoline powered engines. Anything thinner than 5W30 is thinner than optimum, and anything thicker than 5W30 is thicker than optimum.
And it is up to the owner to decide for themselves, what oil they want to use. For me, I now use 5W30 in my stock late model engines, and in my modified High Horsepower engines.
hello 540RAT
excellent content.
allow me to ask the obvious:
Have you developed ANY method to predict IF the addition of OIL EXTREME CONCENTRATE product to the oil will increase/decrease the wear protection psi?
I am perplexed as to how the additive REDUCED the psi when added to the motor oil by the SAME manufacturer.
kudos
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Hi there,
The oil brand does not matter. It’s the particular oil product that matters. What I found was that poor performing oils from any brand, typically had their psi value increased when it was added. And that good performing oils from any brand, typically had their psi value reduced when it was added.
Good performing oils do not need any help. I do not recommend using any aftermarket additives. I recommend selecting a good oil in the first place.
540 RAT..
I was wondering if there was ANY difference in wear protection b/w say, 5W30 Quaker State Ultimate Durability Dexos 1 and the Gen 2 formula?? I ask because I notice in your results how newer iterations of the same base oil doesn’t necessarily lead to improved psi numbers.
I like your personal choice of 5W30 Quaker State Ultimate Durability.. but I recently picked up the Gen 2 formula of the same and I’m a tad worried it’s PSI numbers may NOT be the same as shown for #21 on your current list.
help.
Thanks!
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Hi,
It is not practical for me to re-test dozens, and dozens, and dozens of oils simply because they added the Gen 2 certification. I don’t believe it is a huge change. So personally, I don’t lose sleep over it.
However, I am considering only re-testing 5W30 QSUD. So, that would give us an excellent comparison of one of the top oils.
“I personally use 5W20 QSUD in two of my own late model engines that call for 5W20. But, I would not use 0W20 for the reason mentioned above.”
So you’ve now switched to 5w-30 in those vehicles.
Peter
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Hi Peter,
Yes, I have. I do drive my vehicles aggressively a lot of the time. And 5W30 does typically eliminate minor mechanical noises. That makes 5W30 a much better choice.
Engines were typically designed for 5W30 in the first place. And 5W20 was later called for, just to slightly help increase gas mileage. Though the improvement is usually so slight, that most people can never notice it.
And of course now, there is no going back. Once an Auto Maker starts calling for 5W20, they will stay with it for existing engines and new ones. Except for those who are pushing even further in the wrong direction, and have started calling for insanely thin 0W16.
If you just drive normally in an ordinary daily driver vehicle, then you should not have any problem with 5W20.
wow.
Hello 540 RAT.
so under section 4, you have a list of oils listed with their respective components in brand new state.
what a revelation.
much as the regulators in the food industry demand a listing of all measurable ingredients be listed out on label for the consumer… WHY is it that the auto industry as huge as it is has NOT reached that point in its development?!?
i understand competition, trade secrets etc but heavens above I think everyone reading your stupendous blog would agree that the average consumer NEEDS more than dexos gen 2 pasted onto a quart bottle.
it’s unacceptable.
you, Sir are providing GOLD right here.
thank you!
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Hi again,
Thanks for the kind words. I’m glad to hear that you appreciate my Blog.
Hello 540 RAT.
I am very glad to hear you say you are considering a re-test in the matter of the Gen II formulation.
Where I live, the local shops do carry the FS formula Mobil 1 which is pretty much top-ranking in your list, but the pricing is absurd for my needs.
As I mentioned before, the Quaker State is right on the money. Even a decade ago, I had switched to QS just because I noticed that after I made an impulse buy of a few quarts back then, the oil was still honey brown six months down the road where other well-known brands would be burnt beyond recognition in the same timeframe.
The car started pulling it’s own weight at idle speed too, for the first time..at over 200K on the odo!
I was pleasantly surprised to see their product make top 20 on your list as it were and glad that I switched.
I wait with baited breath to see the results on your test, good Sir.
cheers.
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Hi again,
It’s good to hear about the excellent results you’ve had with Quaker State Motor Oil.
I have an extra new quart of 5W30 Quaker State Ultimate Durability (QSUD) on hand for an upcoming oil change. So, I plan on re-testing it over the 4th of July Holiday break here in the U.S.
So, I’ll be posting its results at that time, along the results from another oil I’ll also be testing at that time.
Longtime reader, firsttime commentor 🙂
Q1/2: How do you select which oils to test? Is there a lab I can send samples of oils to test in similar fashion, and/or would you be able to test samples sent to you? Particularly interested in the new SN+ formulations, and of course QSUD. I do not see OEM formulations, particularly the low viscosity ones from Japanese manufacturers – 0W20/0W16 with high moly content, for example.
Thank you for your time and effort, time well spent reading this blog 🙂
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Hi there, thanks for being a long time reader.
Typically, to justify the time and effort it takes, oils are selected for testing if they are likely to be of interest, and used by a large number of my Blog Readers.
But, there are some brands that have tested so poorly in my previous tests, that I won’t waste my very limited time, to test any more of their products in the future.
I also generally test viscosities that are in the widest use, and are of the most interest, such as multi-viscosity 20wts, 30wts, and an occasional multi-viscosity 40wt.
Oils thinner or thicker than that, either should not generally be used in most applications (thicker oils), or are not used widely enough (the newest watery thin oils) to justify testing. Though that could change over time with the newest watery thin oil’s. We’ll have see how things shake out with those.
There is no lab that performs my proprietary Engineering Test on Motor Oil Wear Protection Capability.
API SN+ formulations will be tested on an individual basis as future tests are performed. There are already some on my Wear Protection Ranking List. It is simply not possible to re-test dozens, upon dozens, upon dozens of oils simply because of the relatively minor addition of the SN+ certification.
Readers can send me oils for testing, if I agree to test them, when my schedule permits. I am currently not accepting any oil for testing because I am simply too busy. And I already have several oils on hand, that are waiting in line for testing when I can get to it.
Take care,
540 RAT
Thank you for your prompt response, and for the good work you continue to do. If you ever have a slot available, do let me know!
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Hi again,
Thanks for the kind words.
Just to let you know. I don’t send out emails from this Blog. But, Blog readers can check in with me any time, here on this Q&A Section.
Take care,
540 RAT
Hello, 540RAT,
I have suggested your blog to some people that I know. They seamed verry interested. Just a little disapointed that în your oil list They are just a few european made oils. Maybe you will test some more.
I wish a Happy Eastern!
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Hi again Gabriel,
As I’ve said many times before, I test oils that people send to me for testing, when my schedule allows.
The European oil’s I have tested already, were also available in the US where I am located. So, the shipping cost was not that high for people to send me those oils.
But, for people in Europe, it is just too expensive to pay for the shipping cost, to send me oils that are only sold in Europe.
Take care,
540 RAT
Hi Rat,
I have a question, more out of curiosity than anything. Why do you think the racing oils that you have tested perform so modestly? With the exception of the Gulf Competition and the Motul 300V, no racing oil on your list is worthy of attention.
1. What do racing oils do (or don’t) differently than regular motor oil?
2. Why the racing offering of an oil brand performs much poorly than the regular variant? (example: Mobil 1 Racing vs Mobil 1 FS; Motul 300V vs 8100 series)
Thank you for your time!
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Hi Timi,
I can’t answer for Oil Companies. You would have to ask them. But, talking to their Customer Service is usually a total waste of time. Because their Agents don’t know much either. About all they can do is provide a little info as to what products they offer. Though you can find that out yourself on the Internet.
We could speculate (guess) the reason is because they sell so little Racing Oil compared to Street Oil, that they don’t want to invest as much money in their Racing Oil. But, guessing of course is not always correct.
Take care,
540 RAT
Hey 540,
Once again, thank you for the continued time spent on providing the valuable information contained in your blog. I have turned a lot of my “car guy” friends on to your blog and I think it has opened a lot of eyes into the world of motor oil performance.
I was wondering if you had any future plans to test the new “amazonbasics” line of full synthetic oil. I am thinking that it is likely a major company making it for them, but it would be interesting to see the results. With how big Amazon has taken off, it wouldn’t surprise me if it started being a big seller….regardless of what the results are.
Thanks,
Ryan
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Hi Ryan,
Thanks for sharing my Blog with others.
Yes, there is no doubt that all Amazon does is put their label on motor oil that is made for them. Many smaller motor oil Companies also do the same thing.
I already have their oil on hand, along with a few other oils, waiting for testing when my schedule allows. Hopefully, I can get to that within the next couple of months.
Take care,
540 RAT
Does the same rule of 5w-30 being a better choice than 10w-30 for old classic cars with flat tappet cams?
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Hi Jorge,
Yes, of course. 5W30’s better flow during cold start-up, and during warm-up, is even MORE important for flat tappet cam engines.
Take care,
540 RAT
Thanks 540 Rat for the extremely well done oil testing you do. You blew apart many of the myths I held dear. Being an Aerospace engineer I never got too involved in oil testing and theory but also being a car and motorcycle guy I was following the myths I was so used to hearing.
Have you tested any of the Chinese oil company Sinopec products? Thanks, Glen
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Hi Glen,
No, I have not tested any of those products. Everything I have tested, is shown on my Wear Protection Ranking List.
Take care,
540 RAT
Hello again.
Regarding The possbilities to send oil to you for testing, could you tell me.,please where should be sent and how much?
Maybe I will find a way to send you some european oils like ELF, Ravenol and why not, The russian Lukoil.
Take care,
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Hi again Gabriel,
I am not accepting any oil for testing at this time, because my schedule is too busy. I only post my Shipping Instructions for a couple of days at a time, when I have the time to accept more oil for testing. And I already have several oils on hand waiting for testing, when my schedule does open up.
Take care,
540 RAT
Hi, 540RAT
OK. I understand the situation.
Looking forward for new test results. Tommorow I will make the oil change with Amsoil signature 5w30.
Take care.
My friend and I read your blog with great interest. The information you have provided has really changed our minds regarding how we think about oil and its Wear Protection Capability. We have question regarding oil change intervals for antique cars. Annually, we put 500 miles on our cars and sometimes closer to 1000 miles if we do a tour. We are using Mobil 1 currently and in the past we have changed the oil every fall before their winter nap. With the oil today and much higher prices, we were wondering if we could go longer between oil changes. Thank you.
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Hi there,
Changing the oil once a year in cars like yours is the recommended ideal interval. The aging process for motor begins when the bottle is opened and it is poured into an engine that gets driven.
With the formula variations of different oils, how the engines were operated, evaporation, ambient temperature, moisture in the air, etc, it is difficult to declare an absolute maximum time limit on how long motor oil can safely be left in an engine such as yours.
So, if you don’t want to follow the recommended ideal once a year oil change interval, you will have to decide for yourself how long you want to go between oil changes. Because I don’t have any data for going beyond that ideal recommended interval.
Take care,
540 RAT
Hi 540 RAT,
Report on my cars:
1. Nissan Almera 1.6 1997 GA16DE non VTC – 260,000km (161,500mi)on odo:
30,000km (approx. 20,000mi) using Mobil 1 ESP 5w30 in 5,000km (3,000mi) oil change intervals – everything fine – no oil consumption – fine operation
2. Nissan Micra 1.6 2010 HR16DE 110hp (same as US avail. engine) – 122,000km (76,000mi) on odo:
22,000km (14,000mi) using Mobil 1 ESP 5w30 same oil change intervals – everything fine – no oil consumption – fine operation
3. Nissan Qashqai J11 2016 (Rogue Sport in U.S.) 1.5 turbo diesel engine tuned at 148hp (110hp factory output) – 27,000km (16,800mi) on odo:
25,000km (15,500mi) using Pentosin Pento Super Performance III 5w30 same oil change intervals – everything fine – no oil consumption – fine operation (in terms of diesel knocks at idle)
4. Audi 80 coupe 2.2T 230hp 1990 – 187,500km (116,500mi) on odo:
15,000km using Valvoline Max Life 10w40 (Red-Semi Synthetic) 5,000km (3,000mi). With this oil, oil consumption decreased to 0.5qt per oil change interval from 3qts per oil change interval using fully synth 5w40 MAG 1 European formula. 0.5qt is practically no oil consumption cause there’s no need to add during these 3,000 miles (indicator max at oil change to mid at next one).
Reading carefully your blog is a mind opening procedure, using only knowledge from physics and simple engineering to understand how an oil behaves – works. And then, there’s nothing left, but to see these facts working for you on your cars.
Me, personally,
THANK YOU!
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Hi again Emmanouil,
Thanks for sharing the information about how things are working out with your cars.
Take care,
540 RAT
Hi, 540 RAČš.
First impressions with Amsoil signature 5w30:a slight higher accelerations, maybe due to better flow în The cvvt System. Also improved fuel consumtion on highway:from 7 liter /100 km with two persons, to 6.5 liter with 4, at a speed of about 140 km/hour.
I think I made a good choice.
Thanks for the advice.
Nice weekend!!!
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Hi Gabriel,
Thanks for the feedback. I’m glad to hear that the Amsoil is working out well for you.
Take care,
540 RAT
Hey there Rat! So I just recently came across this and figured you may be able to help. So on mustangs, the 2013-2014 Boss 302 Coyote motor calls for 5w50 oil. The Gen 2 Coyote (2015-2017 GT) is the exact same motor internally and Ford says it calls for 5w20. What reasoning can you come up with that makes this makes sense? Same motor and Ford saying requires different oils? I have a gen 3 which has been gaining attention due to piston slap and having longblocks replaced. Many people are switching to 5w50 and I can’t get a straight answer to why people are doing this. Do you have any input? Thank you very much for your research and contributions. They mean a lot to us inquisitive type that don’t know as much as you lol.
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Hi Tyler,
Ford and BMW both call for super thick oil in their Higher HP engines. It does NOT make sense to you, because they are dead wrong, meaning it does NOT make any sense at all. This is a huge mistake made by Factories that simply do NOT understand motor oil. Here’s why:
When an oil layer is so thin that it is only an oil “film”, it is the oil’s “film strength” that provides its wear protection capability. And oil film strength is determined by the oil’s additive package, NOT its viscosity.
When an oil layer is thick enough to be actual “liquid” oil, all oils are equal, because all “liquids” are incompressible!!! For that fundamental reason, all incompressible “liquid” oils provide the same wear protection capability. Once again, viscosity has NOTHING to do with the oil’s wear protection capability.
Motor oil viscosity does however, have an effect on oil pressure. But, if an engine is designed properly, thinner reasonable oils can provide excellent oil pressure. So, there is NO beneficial reason to run super thick oils.
So, I am extremely disappointed with both Auto Makers. I would expect much better from them, because they should know better. And BMW had a huge number of rod bearing failures in their High Performance “M” engines, largely because of that.
Ford calls for 5W20 in their normal GT engines, only for slightly improved MPG, and nothing else. That thin oil was forced on Ford Engineers who did NOT want it, just to help increase their C.A.F.E. Numbers. I know this for a fact, because I have spoken with Ford Engineers who told me just that.
“ALL” their Coyote engine variations would be best served with a High Performing 5W30 Motor Oil from my Wear Protection Ranking List, if they are run aggressively at all.
5W20 is thinner than ideal, and anything thicker than 5W30 is thicker than ideal. See my Tech Article on Motor Oil Viscosity Selection, for all the details.
I’m a Degree’d Mechanical Engineer, U.S Patent Holder, Engine Builder, and life-long Mechanic. In fact, I was a Professional Mechanic while going to College. I have wrenched on Cars, Trucks and Motorcycles since I was a teenager.
And I put my money where my mouth is. I have a modified 600 HP Terminator Mustang, 2003 model, which is the first ever Factory Supercharged Mustang. So, taking my own advice, I run 5W30 Quaker State Ultimate Durability full synthetic in it. And the engine is perfect.
I also have 5W30 in my 800 HP, 540 cubic inch, Big Block Chevy Rat Motor. That engine is also perfect.
Using super thick oil is NOT a cure for piston slap, which is caused by excessive piston to cylinder clearance. The cure is to correct the piston to cylinder clearance. And the easiest way to do that, is to replace the engine with a properly built engine. People who switch to 5W50 have no idea what they are doing. Do NOT follow their WRONG idea.
Take care,
540 RAT
Hi 540,
I have a technical question. Im an engineer, too and i question myself, how your exact bench looks like.
you described, what you basicalle did.
I will try to build….
Greetings, Lukas !
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Hi Lukas,
My Engineering Test Procedure and Test Equipment are Proprietary Intellectual Property. So, the specific details cannot be shared. But, as shown in numerous examples throughout my Blog, including flat tappet cams, the test results exactly match real world experience.
In other parts of your original message not shown above, you are confusing motor oils with increased slipperiness due to them having extra friction reducers, with motor oil wear protection capability. But, slipperiness and wear protection capability are absolutely NOT the same thing.
An extra slippery motor may not provide extra wear protection. And an oil that provides excellent wear protection, may not be extra slippery.
Slipperiness comes from friction reducers. But, wear protection capability comes from the extreme pressure anti-wear components in an oil’s additive package.
Take care,
540 RAT
I was curious as to your opinion regarding sulfated ash content. I’m currently using Amsoil SS 0w-20 in a 2019 JGC with the 5.7 Hemi, as well as a 2019 JGC with the 3.6 pentastar engine.
Amsoil technical support stated that this oil is at 1% sulphate ash. Your opinion is greatly appreciated.
When your schedule is available I have some oils i’d like to send in for testing.
Thanks,
L.V Thompson
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Hi there,
I have never heard of JGC. It would be helpful if my readers would clarify unfamiliar references.
I would not be concerned about 1% sulfated ash. Sulfated ash comes from the burning of additive components that are used to create the total base number (TBN) acid neutralizer.
That motor oil has an extra high TBN value of 12.5, because it is intended for extended oil change intervals, where most oils typically have a TBN value of around 8 to 9 or so. Since sulfated ash and TBN are of course linked, a higher TBN number will result in higher sulfated ash numbers.
Keep in mind, that oil meets the requirements of API SN Plus and GM dexos1 Gen2, according to Amsoil. Their motor oils are among the best on the market. So, I would have no concern about using that oil.
But, for the record, I am 100% against extended oil change intervals. See my Tech Article on Recommended Oil Change Intervals, for all details.
I already have several motor oils in line waiting for testing. So, it could be a long time before I can accept any additional oils for testing.
Take care,
540 RAT
I appreciate your input. I should have just said Jeep Grand Cherokee instead of JGC. I agree with you on extended drains, as I change my oil out at 3,000 miles. The tech department from Amsoil responded to me via e-mail listing the Amsoil SS 0w-20 and 5w-20 at 1.22% Sulfated ash content.
Hi 540Rat- I was curious, I recently read about valve spring oilers, and the gist of it was to reduce the temperature of the valve springs. Apparently, in high rpm applications the temperature of the valve springs can get quite high- the article I read claimed the temperature could get to something like 700 degrees ! I can understand how the springs might actually get that hot, but because what read was more or less a sales pitch for their valve spring oilers, was wondering if you knew of any actual experimental data to back it up. Thanks!
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Hi Kevin,
I don’t have any valve spring temperature test data in front of me. And generating our own valve spring temperature data would not be easy to do.
But, I agree, that sounds more like a sales pitch, than something that most people would ever need, because of the valve spring temps they would actually experience.
What they don’t tell you, is that even stock valve springs are typically oiled as part of normal proper engine design.
It would be hard to believe that even NASCAR valve springs would ever see 700*F. They would come to mind as really high rpm endurance engines. They run at around 9,000 rpm, at 190 mph or so, for as much as 500 miles. If ever an engine’s valve springs get worked REALLY hard, it would be theirs. No doubt open wheel race cars like Indy cars would operate in much the same environment.
But, those engines are so highly refined, that I would expect them to already have valve spring oilers, to keep their valve spring temps under control.
For other engines, including other types of race engines, as well as our own engines, I would like to see proof that valve spring temperatures get so high that we need that Company’s valve spring oilers.
I have never had aftermarket valve spring oilers, even in my High Performance engines, nor do I even know anyone who has.
But, with all that said, having valve spring oilers would not hurt anything. So, I have no problem with anyone using them.
Take care,
540 RAT
Hello 540,
Thank you for answering my question !
That is unfortunate, but understandable.
The section with the slipperness makes absolute sense to me. I can clearly imagine the differences. I think i will give that mobil1 fs 0w40 a try and have a look at if it works.
Before i drove with a cheap oil which is claimed to be just the better one with another label on it. But to be honest i lost my trust in assertions like these. Why should they relabel a 60€-Oil and sell it for 17€ ?
I had put in extra zddp, which i calculated to raise it up to 1400ppm. But like you have shown, this also might have negative consequences. Under circumstances i could have killed the camshaft, even if it was great looking while disassembling (cause of another problem with the engine).
This is now my first experience. Now i want to collect experience in using scientific tested oil and have a look if things look better or even worse with it.
I trust in you,
Greetings Lukas
Hello, 540RAT.
I have ordered also Amsoil MT oil, due to good behavior of Amsoil Signature. Am I made a good choice?
Have a nice day!
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Hi again Gabriel,
Amsoil’s products are among the best on the market. So, you should be fine with that.
Take care,
540 RAT
Hi Rat – I have used oil analysis results from the Lexus I have been running the Renewable Lubricants oil in. The iron numbers are unbelievably low for a 5k mile oil change interval. I’ve got three successive results with the vegetable based oil, they’re all pretty spectacular. If you would like to see what Blackstone found, send me an email at lobuxracer…and I will send you my latest results. I am 100% sold on buying their oil in 5 gallon buckets (I have two cars with almost 10 quarts on an oil change) based on what I am seeing from Blackstone and your confirmation the load capacity is near the top of the chart.
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Hi again,
That is excellent feedback that I thought my Blog readers might like to see. So, I posted it here, without your email address.
I only communicate with my Blog readers here on this Q&A Section. So, no emails are involved. But, feel free to share your Lab Test results here if like.
Take care,
540 RAT
How do I search your blog? I have tried and everything comes up blank. I even tried simply Amsoil since I know that is in there, but still nothing.
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Hi there,
I explain how to search my Blog right at the very beginning. Check it out and you will be good to go.
Take care,
540 RAT
Hi 540 RAT,
I’m participating the less possible in your Q & A blog, but … here is my experience about Tech Article 42 and MAF screen removal issues.
I’ve experienced such a “mess” on my Rogue Sport (EU Qashqai) 1.5dCi (turbo diesel) engine, when I deleted MAF honeycomb, in order to achieve max torque and hp values during ECU reflash at WOT. A final achievement of 152hp instead of 110 at 4100rpm and 244lbft from 191 at 1900rpm are welcome.
But despite its supercharged nature, driveability had some issues when throttle was partly (below 0.5) opened in city driving style. I had my car configured like this for more than a year, with 4 in. of pipe deleted along with the filterbox in favor of a K&N cone filter. These 4 inches were housing MAF screen too.
Finally, a month ago, I replaced the whole system in order to have my K&N under cleaning procedure for a few days, with the OEM filterbox and the whole OEM piping, but with a K&N panel specific 1.5dci filter.
First few miles, and I thought that better throttle response was a placebo effect. 500 miles and I really noticed that this response was not only in my mind. What the hell? I asked a Nissan authorised service store engineer and said that MAF screen is for a purpose.
It doesn’t cost more than 10 euros to Nissan factory and plays a significant role in idle to part throttle modes.
Next step was a visit on dyno to see if 152 hp was still there. No, there were not all of them, but consider this: 150.3 hp is not a cry-for loss. On the other hand, better throttle response and faster turbo spool-up at POT (part open throttle) improved everyday driveability.
Apart from this, 241lbf of max torque are available @ 1750rpm instead of 1900+ rpm.
I wrote all these, because Tech Art. No.42 describes a fact that applies to turbo diesel engines too, as far as I’m concerned.
E.C. Greece
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Hi again Emmanouil,
Thanks for sharing that your experience was exactly the same as my new Tech Article 42 describes regarding MAF sensor screen removal. And yes, this applies to all engines.
Take care,
540 RAT
I’m happy to share my results, just not sure how to do that with this interface. I get a PDF from Blackstone. Converting it to anything useful is really ugly. My iron numbers have been 13, 7, 6, 5, and now 4 (ppm) for the last run with a typical interval of 5k miles +/- a little. The iron numbers mean the most to me as iron in suspension is the most abrasive element they check in their testing. My other Lexus doesn’t produce numbers anywhere close to this. The 6, 5, and 4 numbers were all from Renewable Lubricants products, previously I ran Mobil 1 5w-30. I tried Renewable PCMO and HDMO and got slightly different, but still very similar results. I have decided to stick with their PCMO simply because the HDMO has a lower thermal breakdown number. Both clearly provide excellent service and both are unusually stable as evidenced by their ability to maintain load capacity at elevated temperatures. I doubt anyone would be unhappy with either. I recently discovered they have submitted a product for API certification, but when I looked at the numbers they provided, it didn’t look as capable as PCMO or HDMO.
In the end, I am happy to save the underground petroleum for purposes only it can fill while I put a biodegradable product in my engine that rivals the best of the best for performance.
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Hi there,
Thanks for sharing some of your test data.
540 RAT
Rat,
Are you going to test the Amazon Basics 100% synthetic in either 0-20 or 0-30? Im wanting to see how it compares to Walmart 0-20 100% synthetic. They are both inexpensive to buy and I would get whichever one tests better. They are also very popular and used by 100s of thousands of people. Thanks for your blog. Your ranking system goes along with what works on the street! Keep up the good work.
Doug Burnham
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Hi Doug,
I just tested 5W30 amazonbasics full synthetic, because 5W30 is the most commonly used viscosity overall, and is of the most interest to the most people.
I will be posting that test data along with test data from several other oils, within the next couple of days. So, you can then directly compare 5W30 amazonbasics synthetic with 5W30 Walmart synthetic.
Take care,
540 RAT
I have a high mileage 1966 ford and I like the idea of using the high mileage oil to minimize leaks. Can you confirm it’s more beneficial to use conventional oil instead of synthetic to reduce oil consumption? I am currently using the valvoline full syn high mileage silver bottle
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Hi Mark,
Yes, in older engines that use oil, it is well known that they will use the least oil if they are using High Mileage conventional oils vs High Mileage synthetic oils.
For a 1966 engine, I suggest you consider using 10W40 Pennzoil High Mileage Vehicle Conventional oil.
Take care,
540 RAT
540 Rat there is another web site that they say use your information but they don’t have Amsoil listed at number 2 or 3 . Is Amsoil holding 2 and 3 right on. Or has something changed.
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Hi there,
I have “NO” connection to any web site that uses my Engineering Test Data. So, I have no idea what they do with my Test Data.
I suspect what you might be seeing on that web site, is that they did not include “ALL” the oils on my Wear Protection Ranking List, which throws off the ranking numbers they show. If they are doing something more sinister, then they are fraudulently manipulating my information.
You should only come to my Blog to see the FACTS from my Engineering Tests on motor oil. You should not be looking at some second party web site using my information. Because not only can they be confusing, but they could also be providing completely wrong information, that didn’t even come from me.
If you look at my own Wear Protection Ranking List, you will see that Amsoil is ranked 2nd and 3rd. The oil ranked 1st on my list, is an oil that had an aftermarket additive put in it, which I tested for informational purposes only, because of a request I had at that time, to test that additive.
But, I do NOT recommend using any aftermarket additives at all. Because they can make a motor oil WORSE OVERALL, due to upsetting the carefully balanced factory additive package, no matter what it may or may not do for the oil’s wear protection capability. So, I no longer accept any Aftermarket Additives for testing, since it can give my Blog readers the wrong idea about using them.
An excellent performing motor oil will NOT need any help. If you have an oil that needs help, you are using the wrong oil. Anyone can easily find an excellent performing motor oil on my Wear Protection Ranking List, which they cannot find anywhere else.
Take care,
540 RAT
540RAT: Very informative blog and I like the attention paid to shear strength of the oil. In the end that is what keeps parts apart when running at op temp. Also the emphasis on oil flow as key … this has informed me greatly on my choice of oil for my new car.
1) I don’t, however, agree with your opinion on computed oil change intervals. I read (for example) the published paper[1] by Honda on how they arrived at their algorithm for the oil change and it is scientifically, statistically, engineering based through and through – that should meet your standards …. (The owner’s manual still says 1 year max, however, in the case of my car but my oil won’t last that long with my mileage). Yes, I did read your points about the depletion of the additive pack and accumulation of chemical contaminants. That said, I’ve never been disappointed by Honda’s engineers over the last 30+ years and my girlfriend’s first Honda Fit did a lot of road (sales) based on the minder with no issues until she sold it with over 300km (and bought another Fit, of course).
2) Have you spoken with API or oil makers about adding shear strength at operating temperature to oil labels?
3) You say you have no skin in this game. If so, and for the benefit of gear heads everywhere, why not publish the method and apparatus?
Cheers,
The Bull.
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Hi Bull,
1) I do NOT express opinions, nor theories, nor do I speculate in this Blog. I share FACTUAL Engineering Test Data that is determined by the Science of the Physics and Chemistry involved in the testing.
And I provide various recommendations for the BEST way to care for engines, based on reasons I state, which also takes into account decades of hands-on engine experience, and that is all backed-up with being a long time Mechanical Engineer.
My recommendations come from everything just mentioned above, so they are not up for agreement or disagreement. This Blog is not an open debate. If you are looking for that, you need to move on to a Forum, where you can argue endlessly to your heart’s content.
Manufacturers suddenly changed to ridiculously long oil change intervals, with no motor oil changes and no engine changes, only to reduce their “cost of ownership” numbers, regardless of what their propaganda may say.
Using ridiculously long oil change intervals does NOT benefit an engine in any way. It only reduces the Owner’s financial expenditure related to changing the oil. That is most certainly NOT the BEST way to care for an engine.
Sharing information about what is FACTUALLY the BEST way to care for an engine, is what this Blog is all about. FACTS MATTER!!!
Keep in mind that the Honda Fit has a VERY LOW performance engine that does not load its oil heavily like a Higher Performance engine does. So, it is not a good example to use, to make the case for extended oil change intervals.
I have experienced complete used oil failure/seizure during testing of used oil that had as little as little as 5,000 miles on it. That is real world test data, not some theoretical algorithm. So, for that reason and all the reasons I discuss in my Recommended Oil Change interval Tech Article, I stand by my recommendations for oil change intervals that are the BEST way to protect an engine.
My Blog readers are of course free to follow my recommendations for their own benefit, or they can ignore my recommendations and do their own thing. It makes no difference to me either way.
2) No, because half the oils on the market would look so bad, that no one would ever buy them. So, the Motor Oil Industry would never agree to do that. Plus, they would just say that an API SN certification already covers that. But, I have determined that an API SN certification is totally worthless with regard to wear protection capability.
3) My Engineering Testing Methodology and Test Equipment are Proprietary Intellectual Property, and cannot be shared.
Take care,
540 RAT
Hello, again 540RAT,
Just a feedback after 2000km made with Amsoil 5w30 Signature, on Kia ceed 1.4 109 hp:I bearely recognize my engine. Much smooter, lowe fuel consumtion, and the chain noise at idle is reduce drasticaly. Thanks again for your recomandation.
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Hi again Gabriel,
Thanks for your feedback.
But, I do want to be sure everyone is clear about something. I try to not recommend any certain motor oil to people. I have no stake in what motor oil people use.
I provide factual Engineering Test Data, and let people decide for themselves which oil they want to use based on that data.
As I recall, I did not recommend that oil to you. I merely said it would be a good choice, when you asked about it.
Take care,
540 RAT
Hello, 540RAT,
Sorry for the missunderstanding. Of curse you did not especialy recommended. It was enough for me to look on wear ranking.
Nice weekend!
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No problem.
You have a nice weekend too.
540 RAT
Did I miss it or was Amsoil 5W20 Signature not tested? I see the results for Amsoil 5W30 Signature.
Is there that much difference in oil weight from 5W20 vs 5W30? Maybe 5W20 better for Midwest winters and 5W30 for summers – correct?.
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Hi Robert,
My Wear Protection Ranking List has 0W20 and 5W30 Amsoil Signature Series oils right at the top. I did not bother to test 5W20 Amsoil SS oil since I had already tested the other two.
5W20 and 5W30 are both rated as 5wt oils when cold, which applies to both cold engine start-up, and during engine warm-up.
But, 5W20 is rated as a 20wt oil at hot operating temperature, while 5W30 is rated as a 30wt oil at hot operating temperature.
So, their viscosities are comparable when cold, but their viscosities are different when hot.
In general, you can just follow your Owner’s Manual’s viscosity recommendation, and use the same oil year around.
But, also be aware that 5W20 oil came about only to slightly help improve Auto Makers’ C.A.F.E. (Corporate Average Fuel Economy) numbers. It did NOT come about to help the engines in any way.
Virtually any engine that calls for 5W20, can also safely use 5W30. In fact, many engines that call for 5W20 are happier, and make less mechanical noise with 5W30.
5W30 is really the best all around viscosity for most engines. I now use 5W30 in my own stock engines that called for 5W20. And I also use 5W30 in my own modified High HP engines.
So, you can decide for yourself what you want to run.
Take care,
540 RAT
It’s a 2019 KIA Optima and the owner’s manual states both 5W20 and 5W30 – GDI engine. Reading your blog, I thought thinner oil was better?
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Hi again Robert,
Let me clear that up for you and any other Blog readers who may have had the same question.
Part of the confusion probably comes from the fact that my Blog is so incredibly large. So, many important points might easily be missed.
But, In various places in my Blog, I have tried to make it clear that when I’ve pointed out how thinner oils are better, that was primarily aimed at American Hotrod and Race car V-8 guys, who “mistakenly” think that thicker oils, such as 20W50, are needed in High HP engines. But, that is simply not true, and is the “wrong” way to go.
However, modern late model vehicles already call for thin oils. So, they are already doing the right thing.
And like most things in life, there is an optimum motor oil viscosity for most engines. And then there is thinner than optimum, as well as thicker than optimum.
5W30 is the optimum motor oil viscosity overall, for most water-cooled engines, including High HP engines. Any viscosity thinner than 5W30, is thinner than optimum. And any viscosity thicker than 5W30 is thicker than optimum.
So, I personally use 5W30 in all my own engines, from mild to wild. And I recommend that my Blog readers do the same.
Take care,
540 RAT
Hey 540 Rat:
In previous Q&A posts, I read that you stated oil burning engines will consume less oil when using conventional oils vs synthetic oils.
My question relates to the oil selection for a Subaru 3.6L boxer engine. Subaru boxer engines are prone to consuming oil, and the Subaru 3.6L OEM factory fill is 5W30 mineral oil. Does it make sense to use conventional oil in this engine given its tendency to consume oil? I would like to select the best type of oil that minimizes the potential for oil consumption.
Again, I appreciate input, and I further appreciate the work you do on this blog.
Regards,
RG
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Hi RG,
Yes, it is well known that engines that consume oil, will consume the least oil when using conventional motor oil.
Take care,
540 RAT
Hey 540 Rat:
I appreciate your prompt response…thanks. I have been reviewing 5W30 conventional motor oil wear ratings on your blog. I noticed that the wear rating for Castrol GTX 5W30 SN was pretty good. However, since Castrol updated the formulation to Ultraclean to SN+, the wear rating decreased significantly. I am curious if this is going to be a theme with other conventional motors migrating to SN+.
Any suggestions on a 5W30 conventional oil would be appreciated.
Best,
RG
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Hi again RG,
It is too early to say if SN+ conventional oils in general have reduced capability. The Castrol GTX 5W30 “Ultraclean” SN I tested was NOT SN+, it was just SN.
Something that has become clear in my testing, is Castrol has sadly significantly reduced the capability of their motor oils across the board. Apparently this was done deliberately to maximize profits. So, I completely stopped using their products, and do not recommend them to my Blog readers.
So, I suggest that you consider other conventional oil brands, including High Mileage oils, which can be safely run in engines that are not old. That will give you a wider range of oils to consider.
Take care,
540 RAT
Would you treat a boat engine any different when it comes to oil selection? I have a 20′ mercuiser V-6 and they always recommend 25-40 oil but after reading your blog I wonder if that oil has that great of protection during start-up. Water-skiing and running at wide open throttle a lot would stress an engine so I want to ensure the best oil is in this engine. 25W oil seems like it would not flow ideally during startup on the lake when its 60 F ambient although I always idle and warm up after starting. Reading through the blog and Q/A i haven’t seen any speak of boat engines at all so im hoping you could let me know your thoughts. Your blog is a pleasure to read-very informative!
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Hi Mark,
If you were running an actual automotive engine in your boat, then all the same recommendations on this Blog would apply.
But, I have no test data on engines designed specifically for boats, such as your Mercriuser V-6. I’m also not specifically familiar with how capable their oiling systems are, relative to their particular bearing clearances. So, to stay on the safe side, I will not suggest changing the hot 40wt viscosity rating.
However, I will say that a cold 25wt viscosity rating is insanely too thick. So, I definitely suggest you switch to a far superior multi-viscosity rating, such as 0W40, 5W40 or 10W40.
A few oils you could consider, are:
0W40 Mobil 1 “FS” European Car Formula, which is currently ranked 6th on my Wear Protection Ranking List.
Or
5W40 Mag 1, FMX, European Formula, which is ranked 29th.
Or
5W40 Joe Gibbs DT40, which is ranked 50th.
Take care,
540 RAT
I am currently running QSUD5w20 in my 5.0l jaguar. I want to switch to QSUD 5w30. I see from your results i would’nt be giving up much in wear protection. I am more concerned with mechanical noise(reducing it) and potential engine problems, as jaguar dealers are adamant on 5w20, but i can find no supporting info as to why. Your research suggests 5w30 would be ok. Am i missing something that may be unigue to this engine?.
On another note. I have a 4.0l jeep grand cherokee that i switched over, at 160,000km to highly rated high mileage oil from your list and am happy to say that at 310000km my engine idles as smooth as glass and is quiet. Ive heard other jeeps with less mileage rattling like bolts in a metal can.
Keep up the good work
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Hi there,
5W30 is the optimum viscosity for most gasoline powered, water cooled automotive engines. Virtually any engine that calls for 5W20 can safely use 5W30. Engines that call for 5W20 are typically happier and make less mechanical noise with 5W30. I’ve switched my own late model engines that call for 5W20, over to 5W30. And I would do the same thing with your 5.0 Jag.
Jag Dealers are adamant about using 5W20 only because they don’t know any better. They are just blindly following what is called for.
There is no technical benefit for an engine to use 5W20. In fact Engineers did not want 5W20 in the first place. It was forced upon them by Corporate Management to slightly help Corporate C.A.F.E. fuel mileage numbers. The whole thing was Political, not Technical.
Your 5.0 Jag will be fine with 5W30.
Take care,
540 RAT
Hi 540 Rat, I have a variation of the question that you just answered for blackjag2. I have a 2016 jeep grand cherokee that calls from 0w-20 (versus 5w-20) and I’ve been using the Amsoil Signature Series 0w-20 as it’s so highly rated by you. Would I also be ok going to 5w-30 in that engine? Thanks! Dan
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Hi,
Yes, 5W30 would be fine.
Take care,
540 RAT
Hello 540 Rat,
First of all, i thank you for all informations and experiences you’ve shared with us.
Like most of your readers, i would like to know which oil should i use on my Civic FK7 which has 1.5T DI gasoline engine on it. At that moment, my car is around 5k kilometers and i believe i will have to change the engine oil around 2k kms later. Where i live is quite hot, therefore i would like to know if using an engine oil of 5w30 fits or not?
Thanks in advance for your interest.
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Hi there,
Yes, I would use 5W30 in your engine.
Take care,
540 RAT
“There is no technical benefit for an engine to use 5W20.”
Is this a departure from your support (cooler oil) for using 5w-20 in engines designed for it.
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Hi there,
I would not say that I was ever a fan of 5W20. It was more that I just grudgingly accepted it in newer engines.
It would be more accurate to say that most of today’s engines can run 5W20, than to say that they were actually designed for 5W20.
5W20 was forced on Factory Engineers in order to slightly improve Corporate average fuel economy numbers. It was not used to somehow be a technical benefit for engines.
If people feel they need to run 5W20 because that is what the Owner’s Manual says, that is fine. It won’t harm an engine that is just a normal daily driver.
But, for engines that are raced, generally driven aggressively, or used in any extreme condition, 5W30 is a much better choice overall. 5W30 is plenty thin enough to provide excellent lubrication and cooling.
In addition to that, if people were to listen closely to their engine at hot idle, they would find that most of them make some mechanical noise when using 5W20. But, when using 5W30, those engine noises are typically eliminated.
Bottom Line: Like most things in life, there is an optimum for almost everything. And when it comes to motor oil, 5W30 is the optimum viscosity for most water-cooled gasoline powered engines. Anything thinner than 5W30 is thinner than optimum, and anything thicker than 5W30 is thicker than optimum.
And it is up to the owner to decide for themselves, what oil they want to use. For me, I now use 5W30 in my stock late model engines, and in my modified High Horsepower engines.
Take care,
540 RAT
hello 540RAT
excellent content.
allow me to ask the obvious:
Have you developed ANY method to predict IF the addition of OIL EXTREME CONCENTRATE product to the oil will increase/decrease the wear protection psi?
I am perplexed as to how the additive REDUCED the psi when added to the motor oil by the SAME manufacturer.
kudos
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Hi there,
The oil brand does not matter. It’s the particular oil product that matters. What I found was that poor performing oils from any brand, typically had their psi value increased when it was added. And that good performing oils from any brand, typically had their psi value reduced when it was added.
Good performing oils do not need any help. I do not recommend using any aftermarket additives. I recommend selecting a good oil in the first place.
Take care,
540 RAT
540 RAT..
I was wondering if there was ANY difference in wear protection b/w say, 5W30 Quaker State Ultimate Durability Dexos 1 and the Gen 2 formula?? I ask because I notice in your results how newer iterations of the same base oil doesn’t necessarily lead to improved psi numbers.
I like your personal choice of 5W30 Quaker State Ultimate Durability.. but I recently picked up the Gen 2 formula of the same and I’m a tad worried it’s PSI numbers may NOT be the same as shown for #21 on your current list.
help.
Thanks!
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Hi,
It is not practical for me to re-test dozens, and dozens, and dozens of oils simply because they added the Gen 2 certification. I don’t believe it is a huge change. So personally, I don’t lose sleep over it.
However, I am considering only re-testing 5W30 QSUD. So, that would give us an excellent comparison of one of the top oils.
Take care,
540 RAT
“I personally use 5W20 QSUD in two of my own late model engines that call for 5W20. But, I would not use 0W20 for the reason mentioned above.”
So you’ve now switched to 5w-30 in those vehicles.
Peter
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Hi Peter,
Yes, I have. I do drive my vehicles aggressively a lot of the time. And 5W30 does typically eliminate minor mechanical noises. That makes 5W30 a much better choice.
Engines were typically designed for 5W30 in the first place. And 5W20 was later called for, just to slightly help increase gas mileage. Though the improvement is usually so slight, that most people can never notice it.
And of course now, there is no going back. Once an Auto Maker starts calling for 5W20, they will stay with it for existing engines and new ones. Except for those who are pushing even further in the wrong direction, and have started calling for insanely thin 0W16.
If you just drive normally in an ordinary daily driver vehicle, then you should not have any problem with 5W20.
Take care,
540 RAT
wow.
Hello 540 RAT.
so under section 4, you have a list of oils listed with their respective components in brand new state.
what a revelation.
much as the regulators in the food industry demand a listing of all measurable ingredients be listed out on label for the consumer… WHY is it that the auto industry as huge as it is has NOT reached that point in its development?!?
i understand competition, trade secrets etc but heavens above I think everyone reading your stupendous blog would agree that the average consumer NEEDS more than dexos gen 2 pasted onto a quart bottle.
it’s unacceptable.
you, Sir are providing GOLD right here.
thank you!
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Hi again,
Thanks for the kind words. I’m glad to hear that you appreciate my Blog.
Take care,
540 RAT
re: re-testing 5W30 QSUD.
Hello 540 RAT.
I am very glad to hear you say you are considering a re-test in the matter of the Gen II formulation.
Where I live, the local shops do carry the FS formula Mobil 1 which is pretty much top-ranking in your list, but the pricing is absurd for my needs.
As I mentioned before, the Quaker State is right on the money. Even a decade ago, I had switched to QS just because I noticed that after I made an impulse buy of a few quarts back then, the oil was still honey brown six months down the road where other well-known brands would be burnt beyond recognition in the same timeframe.
The car started pulling it’s own weight at idle speed too, for the first time..at over 200K on the odo!
I was pleasantly surprised to see their product make top 20 on your list as it were and glad that I switched.
I wait with baited breath to see the results on your test, good Sir.
cheers.
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Hi again,
It’s good to hear about the excellent results you’ve had with Quaker State Motor Oil.
I have an extra new quart of 5W30 Quaker State Ultimate Durability (QSUD) on hand for an upcoming oil change. So, I plan on re-testing it over the 4th of July Holiday break here in the U.S.
So, I’ll be posting its results at that time, along the results from another oil I’ll also be testing at that time.
Take care,
540 RAT